基于麦克斯韦电桥的互感器负荷箱测试仪的设计

A Design of Load-box Calibration Device by Maxwell Bridge

在互感器负荷箱的日常检测工作中发现,其误差往往出现不稳定的现象,这主要与校准装置的工作原理有关。目前互感器负荷箱校准装置的测量原理为"阻抗检测法"或"导纳检测法",测量结果受电网质量(高次谐波,频率等因素)影响较大,这直接影响着检测结果的可靠性。本文采用麦克斯韦电桥原理,提出独立检测互感器负荷箱内部元件(电阻、电感)的方法,避免了电网不稳定时对校准工作带来的影响,并通过对比试验证明了独立元件测量思想在测量稳定性方面有明显的优势。

In routine testing of load-box,the error often appears instability which related to the principle of detection.At present,the measuring principle of load-box is ＂Impedance detection＂ or ＂Admittance test＂ which is greatly affected by the quality of power grid（such as upper harmonics,frequency and other factors）.As this point,the error of load-box often appears in unstable phenomenon especially in low impedance.Therefore,this paper designs a device to calibration load-box that based on the theory of Maxwell Bridge,and provides a method by detecting the components（such as resistance and inductance） in the load-box which can not only avoid the effect that comes from the grid,but also can offer a basis for developing more accurate device of load-box calibration.Moreover,a comparative experiment has been made between this device and the tradition one,and it proved that the independent component measuring idea has obvious advantages at stability aspect.